East King County Projects

This is part of the conveyance system program created to rehabilitate corroded conveyance pipelines throughout the county’s wastewater system. The first phase of this work is starting this summer; it includes lining of approx. 3,000 feet of sewer pipe located in the city of Bellevue.

The county is continuing construction upgrades to this aging pump station and force main serving City of Kirkland sewer customers. The project will increase pumping capacity, replacing aging equipment, and install larger diameter pipes. Construction started in September 2011 and will be completed in 2014.

To keep up with a growing population, King County is looking at options to improve the sewer system in the Lake Hills and NW Lake Sammamish areas. Increasing sewer capacity will allow King County to continue to safely and reliably move wastewater flows to be treated at a regional treatment facility. King County will review project options over the next year and start design in 2016. Construction is expected to begin in 2018.

Currently, flows from the North Lake Sammamish basin are routed to the South Treatment Plant through the East Side Interceptor (ESI). This project will divert up to 43 million gallons per day of wastewater from the North Lake Sammamish basin and send these flows to the Brightwater Treatment Plant. This project is necessary to maintain the ability of the ESI to convey peak flows during a 20-year storm event. The ESI is expected to reach peak flow capacity in 2021. Construction is scheduled to begin in 2017.

This project will increase the capacity of the existing North Mercer Island Interceptor and Enatai Interceptor components of the regional wastewater system in order to convey the 20-year peak wastewater flows projected through the year 2050.